Rule History

alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Valkyrie Stealer Data Exfiltration Attempt M2"; flow:established,to_server; http.method; content:"POST"; http.uri; bsize:8; content:"/api/log"; http.header; content:"X-API-Key|3a 20|"; pcre:"/^[A-Za-z0-9]{32}/R"; http.request_body; content:"name|3d 22|iv|22 0d 0a 0d 0a|"; pcre:"/^[a-f0-9]{24}/R"; content:"name|3d 22|tag|22 0d 0a 0d 0a|"; pcre:"/^[a-f0-9]{32}/R"; content:"name|3d 22|blob|22 3b 20|filename|3d 22|encrypted.bin|22|"; content:"name|3d 22|data_json|22|"; fast_pattern; content:"|22|antivirus|22 3a|"; content:"|22|browsers_processed|22 3a|"; content:"|22|build_id|22 3a|"; reference:md5,7592ee0bba0c9cae1e26de5e3a9675ef; reference:url,x.com/suyog41/status/1981257934446481622; classtype:trojan-activity; sid:2065385; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, attack_target Client_Endpoint, created_at 2025_10_24, deployment Perimeter, malware_family Valkyrie_Stealer, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_10_24, mitre_tactic_id TA0009, mitre_tactic_name Collection, mitre_technique_id T1005, mitre_technique_name Data_from_local_system; target:src_ip;)